Screw-spike.



E. C. HOLMES.

SCREW SPIKE.

APPLICATION FILED Aue.2fi. 191s.

L fiwo Patented Feb.11,1919.

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new c. Romans, or nonwoon, OHIO.

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Specification of Letters Patent.

Patented Feb. 11, 1919.,

Application filed August 26, 1915. Serial a... 47,407.

To. all whom it may concern:

Be it known that I, EDWARD O. HoLMns, a citizen of the United States, and a resident of the city of Norwood, in the county of- Hamilton and State of Ohio, have invented certain new and useful Improvements in Screw-Spikes, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming part of this specification.

My invention relates to screw spikes especially adapted for securing rails to the sleepers in railway track construction and for other construction work, and the object of the invention is to provide a screw spike that may be screwed to place without any preliminary boring of a hole for its reception even in the hardest and toughest of woods, and which can be screwed to its seat with a simple hand wrench.

Spikes for railway track construction must be of comparatively large size, from six to seven inches in length and about an inch in diameter, and it has required the devising of many constructions and much experimentation-to arrive at a form of construction best adapted for the purpose specified, which shall have the requisite holding power and which can be started and driven to its seat without preliminary work, and which is so constructed as not to mutilate and destroy the fibers or split the wood, and which at the same time shall prevent water and moisture seeping around the spike.

The various objects above set forth I have attained by that certain novel construction of spike to be hereinafter particularly pointed out and claimed.

In the drawings, V

Figure 1 is a front elevation of my im-" proved spike.

Fig. 2 is a similar elevation of the screw threaded portion of the spike, taken at an angle of ninety degrees to Fig. 1. p

Fig. 3 is a diagrammatic section showing the screw shank and the flutes straightened out so as to illustrate the depth of the flutes at various points alon the shank.

Fig. 4.- is a bottom p an view.

Fig. 5 is a diagrammatic illustration of the screwthreads to show the difference in pitch of the upper and lower sides of the threads.

' The head 1 of the spike is preferably formed with flat sides, slightly inclined to 4 accommodate the wrench for driving the screw to place, and a flanged base 2 to engage over the edge of the rail in track construction. The shank 3 of the screw is cylindrical in shape and of uniform diameter throughout. The screwthreads 4: are out with the pitch of the upper surfaces of the threads of substantially seventy-five degrees and the lower surfaces on a pitch of sixty degrees, as indicated at 5 and 6 in Fig; 5. The threads are not ll-shaped, but a substantial base 7 is provided forming part of the cylindrical surface of the spike.

The threads are cut to the drill portion 8 at the lower end of the screw. This point 8 is substantially of the shape of the standard drill of the size of the screw.

Two spiral flutes 9, 10, are cut transverse the screwthreaded portion, so that the flutes it shall have half a turn, and the flutes are deeper at the drill portion and taper upward from the point of the drill to a point about midway of the screwthreaded portion, as indicated in Fig. 3 by the lines 11, 12, showing the depth of the flutes, or the thickness of the web at the base of the flutes. The flutes are out with a half round cutter, so that the shape of the base of either flute is semi-circular. The cuttin of the flutes leaves the drill point 8 wit two straight prutting edges 13 and 14, as indicated in 1g. at.

I have discovered that with a screw spike formed as above indicated, it will cut its own way into the hardest timber, that it takes out less wood than a screw with V-shaped threads and that the flutes balance each other and take care of the chips. The screw as it is driven in cuts the threads in the timber without mutilating the wood, and the threads form a tight seat, preventing any moisture from entering along the threads. By forming the upper thread at a seventy-five-degree pitch, greater resistance is obtained for the holdin of the spike, so that a single operator witli a twelve inch wrench can easily and rapidly drive the screws to place at any perfect water-tight seat is formed for the screwthreads.

\ With the screw spikes of ordinary construction which are now goin into use in track work, it is necessary to ore preliminary holes in the Sleepers, and thus it frequently happens that the holes are not bored in exactly the right place. With my improved construction, the screw spikes can be screwed to place at the exact point desired as rapidly as the ordinary spike can be driven.

I have found that by tapering the depth of the flutes and providing the deepest portion of the flute at the drill end, that the chips cut by the drill are readily taken care of and do not pack around the drill point, preventing its being driven easily into the wood.

Having thus described my invention, what I claim as new and desire to secure by Let ters Patent, is

1., A screw spike comprisinrr a head having a shank of uniform diameter t iroughout, with screwthreads formed thereon, and a drill at messes the end of the shank with a pair of spirally arranged flutes of uniform curvature on opposite sides of the shank, the flutes being deeper at the drill point and shallower upward.

2. A screw spike comprising a head having a shank of uniform diameter throughout,

with screwthreads formed thereon, and a drill at the end of the shank with a pair of spirally arranged flutes of uniform curvature onopposite sides of the shank, each flute being given half a turn, the flutes being deeper at the drill point and shallower upward.

EDWARD C. HOLMES. Witnesses LORENZ S. SEMPLER, KATHERINE SMITH. 

